Injection Stretch Blow Molded Polylactide Bottle and Process For Making Same

ABSTRACT

An injection stretch blow molding process for making containers from a polylactic acid resin. In one aspect the process comprises molding the polylactic acid resin into a perform, applying heat to the perform, stretching and blowing the perform in axial and radial dimensions in order to form a preliminary molded container, conditioning the molded container pursuant to a first conditioning method, conditioning the molded container pursuant to a second conditioning method, and stretching and blowing the molded container in order to form a final molded container. Relatively rigid bottles constructed in accordance with one or more processes disclosed herein are also contemplated.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon, and claims priority to U.S. ProvisionalPatent Application No. 60/895,776, entitled Injection Stretch BlowMolded Polylactide Bottle and Process For Making Same, filed Mar. 20,2007. The entirety of such provisional patent application, including allexhibits and appendices, are incorporated herein by reference.

FIELD OF THE INVENTION

Aspects of the present invention relate to the use of polylactide resin(PLA) in an injection stretch blow molding process to manufacturedurable and relatively thick-walled containers suitable for repeateduse. Other aspects of the present invention relate to PLA bottlesproduced using the processes described herein.

BACKGROUND OF THE INVENTION

Containers such as water bottles are often molded from thermoplasticresins such as polypropylene, PVC, PET and polycarbonate. Polycarbonate,in particular, is the material of choice for clear and durable thickwalled drinking containers used for non-carbonated drinks. Suchcontainers are often used by outdoor sporting enthusiasts and for babybottles. The advantages of polycarbonate include high clarity, highimpact resistance and non retention of odors. Drawbacks of polycarbonateinclude the fact that it is produced from non renewable resources and isthus difficult to dispose of at the end of its useful life. In addition,concerns have surfaced regarding the effects on human health due topotential leaching of residual monomers during contact with liquids.Environmental and resource conservation concerns have led to anincreasing demand for substitute polymeric materials which are derivedfrom renewable resources that will biodegrade in compost facilities aswell as fit into the existing disposal/reuse recycling systems in usetoday.

Polylactide resins (also known as Polylactic acid or PLA) are availablecommercially. PLA is produced from annually renewable resources such ascorn or sugar beet. In addition PLA is easily composted to producecarbon dioxide and water. There are no known health issues associatedwith PLA products in the marketplace today. For these reasons there issignificant interest in replacing polycarbonate with PLA, particularlyin bottle and container applications.

Previous attempts at using PLA to produce injection stretch blow molded(ISBM) bottles have focused exclusively on thin-walled single useproducts such as those used in short shelf life applications like stillwater, juice, oils and milk. U.S. Pat. No. 5,409,751, the details ofwhich are incorporated into the present disclosure by reference,describes such a process. The process described in U.S. Pat. No.5,409,751 involves first forming a preform, or “plug”, which is hollowand has dimensions far smaller than that of the final container. Thepreform is molded into a container by inserting it into a mold, andstretching it both axially (i.e. along its length) and radially. Theaxial stretching is done mechanically by inserting a pusher rod into thepreform and mechanically extending it towards the bottom of the mold.Radial stretching is accomplished by injecting a compressed gas into theplug, thereby forcing the resin outward to contact the interior surfaceof the mold. Typically, a preliminary radial stretch is preformed byinjecting a first increment of gas. This makes room for the stretcherrod, which can then be inserted. The preform is then stretched andimmediately afterward is blown with more gas to complete the blowmolding operation.

ISBM processes are generally divided into two main types. The first is aone-step process, in which the preform is molded, conditioned, and thentransferred to the stretch blow molding operation before the preform hascooled below its softening temperature. The second type of ISBM processis a two-step process in which the preform is prepared ahead of time andstored for later use. In the two-step process, the preform is reheatedprior to the initiation of the stretch blow molding step. The two-stepprocess has the advantage of faster cycle times, as the stretch blowmolding step does not depend on the slower injection molding operationto be completed. However, the two-step process presents the problem ofreheating the preform to the stretch blow molding temperature. This isusually done using infrared heating, which provides radiant energy tothe outside of the preform. It is sometimes difficult to heat thepreform uniformly using this technique and unless done carefully, alarge temperature gradient can exist from the outside of the preform tothe center. Conditions usually must be selected carefully to heat theinterior of the preform to a suitable molding temperature withoutoverheating the outside. The result is that the two-step process usuallyhas a smaller operating window than the one-step process.

In the two-step process, the preform is generally heated to atemperature at which the preform becomes soft enough to be stretched andblown. This temperature is generally above the glass transitiontemperature (Tg) of the PLA resin. A preferred temperature is from about70 to about 120° C. and a more preferred temperature is from about 80 toabout 100° C. The transition temperature is dependent upon the specificPLA resin being used. In order to help obtain a more uniform temperaturegradient across the preform, the preform may be maintained at theaforementioned temperatures for a short period to allow the temperatureto equilibrate.

Mold temperatures in the two-step process are generally below the glasstransition temperature of the PLA resin, such as from about 30 to about60° C., especially from about 35 to about 55° C. Sections of the moldsuch as the base where a greater wall thickness is desired may bemaintained at even lower temperatures, such as from about 0 to about 35°C., especially from about 5 to about 20° C.

In the one-step process, the preform from the injection molding processis transferred to the stretch blow molding step while the preform isstill at a temperature at which the preform becomes soft enough to bestretched and blown, again preferably above the Tg of the resin, such asfrom about 80 to about 120° C., especially from about 80 to about 110°C. The preform may be held at that temperature for a short period priorto molding to allow it to equilibrate at that temperature. The moldtemperature in the one-step process may be above or below the Tg of thePLA resin. In the so-called “cold mold” process, mold temperatures aresimilar to those used in the two-step process. In the “hot mold”process, the mold temperature is maintained somewhat above the Tg of theresin, such as from about 65 to about 100° C. In the “hot mold” process,the molded part may be held in the mold under pressure for a shortperiod after the molding is completed to allow the resin to developadditional crystallinity and relax residual stresses in the amorphousphase (commonly referred to as heat setting). The heat setting tends toimprove the dimensional stability and heat resistance of the moldedcontainer while still maintaining good clarity. Heat setting processesmay also be used in the two-step process, but are used less often inthat case because the heat setting process tends to increase cycletimes.

Blowing gas pressures in either the one-step or two-step processestypically range from about 5 to about 50 bar (about 0.5 to about 5 MPa),such as from about 8 to about 45 bar (about 0.8 to about 4.5 MPa). It iscommon to use a lower pressure injection of gas in the preliminaryradial stretch, followed by a higher pressure injection to complete theblowing process. ISBM processes can further be defined as either asingle blow process, where the preform is stretched to its final shapein a single blowing process, or a double blow process, where the performis first blown followed by a second blow process using the previouslyformed bottle.

Nalgene® is one of the registered trademarks of Nalge NuncInternational, or its subsidiaries. One of Nalge's major products is aline of clear plastic drinking water bottles of various size marketed tooutdoor enthusiasts. Produced from polycarbonate by an Injection StretchBlow Molding Process (ISBM), the key properties of these bottles arehigh impact resistance and resistance to staining. In addition, they donot retain odors, are capable of withstanding sub-freezing to boilingtemperatures, are dishwasher safe away from the heating element, and canwithstand temperature ranges of 135° C./275° F. to −135° C./−211° F.These properties make the Nalge bottles, and others formed from asimilar polycarbonate, appealing to consumers who need a durable andreusable bottle for various activities.

The polycarbonate material these bottles are formed from is an amorphouspolymer with a glass transition temperature of approximately 148° C. Thematerial has high toughness, transparency and very low moistureabsorption as additional positive attributes for this market. However,these polycarbonate bottles have several negative attributes includingthat they are derived from non-renewable oil based resources, have highmelt processing temperatures of approx 200C, and have a relatively highmaterial cost.

In addition, since 1993, increasing health concerns have been raisedover the extraction of bisphenol A into the water contained inpolycarbonate bottles. See, Our Stolen Future atwww.ourstolenfuture.org; The ecological footprint of Nalgene waterbottles (2006) Deanna Thompson, Kyla Patterson, Elizabeth Whittaker, &Sally Haggerstone. Bisphenol A is also used in other resins such asepoxies and has been associated with chromosomal aberrations, thusraising questions about the safety of consumer products made withpolycarbonate, especially when they are designed to contain food orwater. The research on chromosome damage, by a team of Case WesternReserve scientists, found that bisphenol A leaching out of polycarbonatebottles used to provide water to mice caused a chromosomal error in celldivision called aneuploidy. In humans, aneuploidy is one the largestcauses of miscarriages and birth defects, including Down Syndrome. Whilethe link to humans is not conclusive, the process of cell division inmice is very similar to that of humans, and scientists suspect that thecauses of aneuploidy in humans should be similar if not identical.Another issue of concern is the environmental emissions involved in boththe manufacture of the monomers and polymer (2). Thus there is a need tooffer a replacement to these rigid, durable and reusable bottles thatoffers the same performance characteristics while eliminating thenegative attributes associated with their use.

Polycarbonate bottles, such as the clear Nalgene® type found in manyoutdoor sporting goods retail stores, are typically made by one or moreof the same injection stretch blow molding process known and describedabove.

Despite the foregoing, it has until now been difficult to producerelatively thick walled (e.g. >30 mil or 0.76 mm) PLA bottles thatmaintain their thermal stability and rigidity through these conventionalISBM processes. There is no indication that anyone has been successfulto date in developing a process for rigid PLA bottles that utilizes thedouble blow ISBM technique. Furthermore, single blow PLA processes havenot been successful at producing a reusable bottle that can maintain therigidity and thermal stability necessary for such applications describedabove.

PLA products have high MVTR and high oxygen and carbon dioxidetransmission rates which exclude PLA bottles from the longer lifebeverage/drinks bottle applications and carbonated soft drinks markets.However, the properties of PLA for the short shelf life, more durablenon-carbonated market segment presently occupied by polycarbonateNalgene®-type bottles, hold significant potential to meet the functionalrequirements of this market segment. In comparison to polycarbonate, PLAhas superior oxygen and carbon dioxide permeability although, as alreadynoted, the carbon dioxide permeability of both polymers makes bothunsuitable for the carbonated drinks market Laboratory testing of PLAsingle use bottles and prototype durable thick walled bottles has shownthat PLA bottles survived the industry drop test of 3 meters ontoconcrete and a 45 degree angle with the bottle full of water. Thus, itis contemplated that thick walled PLA bottles will also meet the marketrequirements for the more durable, transparent, refillable,non-carbonated market segment presently occupied by polycarbonatebottles. Aspects of the present invention also relate to the reusablecontainers produced in accordance with the manufacturing processesdescribed below.

SUMMARY OF THE INVENTION

An injection stretch blow molding process for making containers from apolylactic acid resin. The process comprises molding the polylactic acidresin into a perform, applying heat to the perform, stretching andblowing the perform in axial and radial dimensions in order to form apreliminary molded container, and conditioning the molded container.

Another aspect of the present invention includes an injection stretchblow molding process for making containers from a polylactic acid resin.The process comprises molding the polylactic acid resin into a perform,applying heat to the perform, stretching and blowing the perform inaxial and radial dimensions in order to form a preliminary moldedcontainer, conditioning the molded container pursuant to a firstconditioning method, conditioning the molded container pursuant to asecond conditioning method, and stretching and blowing the moldedcontainer in order to form a final molded container. Relatively rigidbottles constructed in accordance with one or more processes disclosedherein are also contemplated.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects and advantages and a more complete understanding of thepresent invention are apparent and more readily appreciated by referenceto the following Detailed Description and to the appended claims whentaken in conjunction with the accompanying Drawings wherein:

FIG. 1 is a schematic diagram/flow chart of a single blow ISBM process;

FIG. 2 is a schematic diagram/flow chart of a double-blow ISBM process;and

FIG. 3 is a drawing showing the details of a representative PLA bottleproduced pursuant to one or more of the processes described herein.

DETAILED DESCRIPTION

Aspects of the present invention relate to ISBM manufacturing processesfor producing relatively thick walled containers from a PLA resinwherein (1) the PLA is a copolymer having repeating L and D lactic acidunits in which either the L or D units are the predominant repeatingunits and the predominant repeating units constitute 90 to 99.5% of thelactic acid repeating units; (2) the product of axial and radial stretchratios is from about 3 to about 17.5; and (3) where the wall thicknessof the final container is from about 30 to about 80 mils, although wallthicknesses greater than 80 mils are also contemplated in someembodiments.

Due to the environmental concerns associated with polycarbonatediscussed above, for short shelf life outdoor sporting applications,transparent bottles meeting the performance requirements of this marketsegment could be produced from a renewable resource based polymer suchas Polylactic acid (PLA). PLA polymers are already in the marketplacefor single use, short shelf applications such as non carbonated watersold through retail stores. Because of their low wall thicknesses (10-12mil), which leads to low durability, poor impact performance, and lowtemperature performance (130° F./55° C.), these single use products willnot meet the demands of the outdoor multiple use sporting goods market.It has been shown in connection with aspects of the present inventionthat these issues can be overcome by the use of various heat-settingtechniques and modifications to ISBM processes.

The ISBM process in accordance with aspects of the present invention canbe either a one or two step process as described more fully below andcan utilize either a single blow or a multiple blow process. While notspecifically required, in preferred embodiments, a double blow processhas been shown to yield desirable results. It should be noted that whilesome embodiments within the specification might be referred to aspreferred, this language is not intended to limit the scope of theclaims to these specific embodiments, unless specifically indicated inthe specification and claims. The claims are meant to encompass thebroadest interpretation that is consistent with the plain meaning of theterms as confirmed by the specification.

As described more fully below, the use of PLA resin within theprocessing guidelines and specific manufacturing specifications statedbelow and as set forth in the appended claims, allows for containers tobe produced through an ISBM process that have controlled crystallinity,good clarity, good impact performance, and increased thermal stabilityover previously produced PLA containers.

In general, thick walled containers in accordance with aspects of thepresent invention are made using an injection stretch molding (ISBM)process. Such ISBM processes are well known, being described for examplein U.S. Pat. No. 5,409,751, the details of which are incorporated intothe present disclosure by reference in their entirety, and furtherdescribed in FIG. 1. The generalized ISBM process 100 involves firstforming a preform or “plug” at step 102 which is hollow and whosedimensions are a fraction of those of the final container. The performgeometry is specifically designed to produce a container of a determinedgeometry. The preform can be formed, conditioned, and transferred to thestretch blow molding operation before the preform is cooled below itssoftening temperature at step 104. This process is commonly referred toas a “one step” process since the perform is prepared and blown into acontainer in a single step, prior to the perform cooling.

In another well known process, the preform is allowed to cool below itssoftening point and can then be stored for use at a later time at step103. The preform is then reheated to carry out the stretch blow moldingprocess when needed at step 104. This process is commonly referred to asa “two-step” process. Conditioning step 106 may be carried out dependingon the specific application. After any such conditioning, the finishedbottled is ejected from the processing machine at step 108

The two step process is most often employed for the manufacture of thickwalled durable containers such as the Nalgene-type bottles describedabove. The two-step process has the advantage of faster cycle timessince the stretch molding process step does not depend on the slowerpreform injection molding process. Additionally, for the production ofthick walled containers the preform temperature can be accuratelycontrolled to allow even material distribution and stress distributionin the final part, thereby providing the required durability androbustness required.

In a double blow process, the following general steps are utilized. FIG.2 describes such a process 200. First a preform is prepared at 202 andreheated and/or conditioned. Preferably, the preform is rotated duringthis process to ensure a consistent reheat. Next, during a primaryblow-molding step 204 the reheated preforms are stretch blown in aprimary stretch blow mold. Next, in a first conditioning step 206, heatsetting or some other type conditioning is achieved. Heat setting can beperformed through, for example, a direct contact procedure. Next, asecond conditioning step 208 is applied, for example heat processing inan oven or other contained environment. Finally, the bottle undergoes afinal blow-molding step 210 in which the bottle takes its final formprior to being ejected from the processing equipment 212. Variousmodifications to one or more of the above double-blow process are knownin order to fine tune the resulting bottle. However, no one hasattempted to use a double blow ISBM manufacturing process in order tocreate a relatively thick-walled and rigid PLA bottle in accordance withone or more aspects disclosed herein.

The controlled reheating of the preform and the subsequent stretch blowmolding step are also highly dependent on the grade of PLA resinutilized. Typically, the three significant resin variables are: 1)molecular wt, 2) viscosity versus temperature, and 3) enantiomeric ratio(L to D ratio). All three variables must be carefully selected andcontrolled to enable a practical processing window for the manufactureof thick walled containers. The correct selection of the resin grade isalso essential if high clarity is also required in the final part.Examples of enantiomeric ratio, extensional viscosity and molecularweight information can be found, for example, in PCT Patent Applicationpublication No. WO2006/002409 assigned to NatureWorks LLC. The detailsof this reference are hereby incorporated into the present disclosure byreference in its entirety.

Mold temperatures in a two-step process are generally held below theglass transition temperature of the PLA resin, typically from about30-60° centigrade and most preferably in the 35-55° centigrade range.

In order to obtain the required dimensional stability in the finalcontainer it may be necessary or preferable to include a “heat setting”step. In one example, the mold temperature may be raised to 65-100° C.and the molded part held under controlled pressure for a short period oftime. This allows stress relief and increased crystallinity to developwhile maintaining the clarity in the part.

EXAMPLES

The following represent various examples and processing results relatedto the use of one or more different types of ISBM processes to process arelatively think-walled container from PLA resin. As stated above, theseexamples are not meant to limit the scope of the claims but are providedas representative examples.

Example 1

0.5 liter bottles were prepared from specific PLA resins in a two-stepISBM process as follows. Preforms having a weight of 100-180 gms wereprepared via injection molding by heating the resin to a temperature of200-220° and injecting the resin into a preform mold specificallydesigned for PLA and the final container dimensions. Such a performdesign takes into account the different extensional viscosity propertiesof PLA compared to other polymers. The molding conditions were optimizedto produce performs with even wall thickness, minimal part stress andclear parts free of haze. The preforms were cooled to room temperaturebefore stretch blow molding in a separate step. Stretch blow molding wasaccomplished using a typical stretch blow molding machine used for PETor PC bottles at cycles of up to 2000 bottles/hour.

The PLA resins used were 1) a first copolymer of 96% L and 4% D having arelative number average molecular wt of above 100,000, and 2) a secondcopolymer of 98.4% L and 1.6% D having a relative molecular wt. of above100,000. Alternately, the perform weight can be in the range of 100-180gms. Alternatively, the above example may be performed via a one-stepprocess, where the conditioning step is eliminated.

Example 2

Overview—PLA bottles were produced at several blow molding conditions todetermine the effects of heat set blow molding and the double blowmolding process on the thermal stability of PLA bottles. The blowmolding conditions used to produce bottles are summarized below.

1. Standard 45° F. mold temperature (to use as reference)

2. Double blow molding process (200° F. mold temperature for bothpasses)

3. 160° F. Mold setpoint temperature

4. 165° F. Mold setpoint temperature

5. 170° F. Mold setpoint temperature

6. 175° F. Mold setpoint temperature

7. 180° F. Mold setpoint temperature

8. 190° F. Mold setpoint temperature

9. 200° F. Mold setpoint temperature

10. 220° F. Mold setpoint temperature

11. 200° F. Mold setpoint temperature with 110° F. base temperature

Thermal Stability—Six (6) bottles, from sets 1-10 listed above, weretested for thermal stability at 150° F. The diameters, height and volumeof each bottle were measured before placing the empty bottles in an ovenat 150° F. for 24 hours. Once the bottles were removed from the oven andcooled to room temperature, they were re-measured. The difference ofthese measurements was reported as a percent change. If the bottlesshowed excessive shrinkage at the 150° F. storage temperature, the oventemperature was reduced in 10° F. increments for the storage untilacceptable shrinkage was observed.

Color and Haze Testing—The color and haze of the bottle sidewall from 1bottle of sets 1-10 was measured at the top and bottom of the panel ofthe bottle.

Crystallinity via DSC—The crystallinity in the center of the panel areaof the bottle was measured for sets 1-10. The crystallinity was also bemeasured in the base of sets 2, 10, and 11. Finally, the crystallinitywas measured in the finish for sets 2 and 10.

In this example, the effects of mold temperature and the use of a doubleblow process on PLA container thermal stability was investigated.Preforms were injection molded using NatureWorks 7032D PLA resin and aColormatrix toner/reheat additive. Injection molding techniques wereused to mold a 40 g PLA perform designed to blow mold into an 18 ozBoston round container. These preforms were then blow molded using aSidel SBO 1/2 single cavity blow molding machine. Once conditions thatproduced an acceptable bottle were determined, bottles were produced atseveral blow mold temperatures for thermal stability testing.Approximately 50 bottles were produced using a 200° F. mold. Thesebottles were then taken and re-blown for thermal stability testing.Results showed that, in general, as the blow mold temperature set pointincreased, the thermal stability of the bottle also increased. Also,bottles that are double blown also displayed improved thermal stability.

Injection Molding—The PLA resins in the previous example were driedovernight at 176° F. to achieve a moisture level below 250 ppm prior toinjection molding. Once dry, the appropriate amount of Colormatrix80-740-2 reheat toner was added to an aluminized mylar bag, then purgedwith nitrogen and sealed. The aluminized Mylarbags were then placed on atumbler for 10-15 minutes to allow an even distribution of material. Theresin samples were injection molded on an Arburg 420M reciprocatingscrew injection molding machine using a 40 g preform tool designed toblow mold into a thick-walled 18 oz Boston round container. Thefollowing table summarizes the injection molding conditions used forthis trial. Approximately 300 preforms were produced using theseconditions.

7032D + Colormatrix Variable Description 80-740-2 Injection MoldingConditions Machine #6 Arburg 420 M Preform # PRE-5568 1 Preform Weight(g) 40.3 Relative Humidity 21% Dew Point (° F.) 53 Mold Temp (° F.) 60Ambient Temp (° F.) 74 Dryer Temp (° F.) 175 Barrel Temperatures Feed (°C.) 215 Zone 2 (° C.) 216 Zone 3 (° C.) 215 Zone 4 (° C.) 216 Nozzle (°C.) 212 Injection Injection Pressure 1 (bar) 800 Injection Time (sec)4.0 1st Injection Speed 12.0 (ccm/sec) 2nd Injection Speed 10.0(ccm/sec) Holding Pressure Switch-Over Point (ccm) 8.0 1st Hold Pressure(bar) 250.0 2nd Hold Pressure (bar) 200.0 3rd Hold Pressure (bar) 100.01st Hold Pr. Time (sec) 2.0 2nd Hold Pr. Time (sec) 3.0 3rd Hold Pr.Time (sec) 2.0 Remain Cool Time (sec) 16.0 Dosage Circumf. Speed (m/min)12.0 Back Pressure (bar) 25.0 Dosage Volume (ccm) 45.0 Meas. Dosage Time(sec) 5.1 Cushion (ccm) 7.4 Adjustment Data Cycle Time (sec) 33.1

Blow Molding—Preforms were then blown using a Sidel SBO1/2 blow moldingmachine. Conditions were optimized for the best section weights andoverall consistency that could be achieved. Even material distributionthroughout the sidewall of the container is addressed through preformdesign modifications.

Initially the blow mold set point temperature was 160° F. Approximately10 bottles were produced at this condition. Next, the blow mold setpoint temperature was increased in 5-20° F. increments until acceptablebottles could not be produced. 10 bottles were collected at each blowmolding interval and tested for color, crystallinity and thermalstability. Bottles were first blown under heat set conditions,increasing mold temperatures by 10° F. until an acceptable bottle couldno longer be produced. The highest mold temperature that could be usedto produce bottles was 220° F. One bottle from each of these blowmolding conditions was placed into an oven overnight at 150° F. Thesebottles were visually inspected the following morning. Observationindicated that bottles that were blown using a 200° F. set pointtemperature appeared to shrink and deform the least.

On the second day of blow molding, the mold temperature of the base wasincreased in increments of 10° F. until the base of the bottle began toroll out. Once this temperature was determined, it was reduced 10° F. toproduce 50 samples for the double blow process. These bottles were thenpassed through the blow molder oven in order to shrink the bottle andrelax the existing stress in the bottle's sidewall. Since wall thicknessof the bottles is thin compared to the preforms, less heat was requiredto reheat the bottles compared to the preforms. To achieve this, one ofthe oven banks was turned off and the blow molder's speed was increased.Blow molding conditions were further optimized to produce a double blowncontainer with the best distribution that could be achieved.

The following table includes the conditions used to blow mold eachcondition. Note that the condition No. 11 was used to produce the firstpass

Blow Molding Conditions 7032D + 7032D + CM 80- CM 80- Resin 7032 D 7032D 7032 D 740-2 740-2 Speed (bph) 500 900 500 500 500 Overall 43 45 37 3737 Oven Lamp Settings Zone 10 0 55 0 0 0 Zone 9 0 55 0 0 0 Zone 8 55 5555 55 55 Zone 7 55 45 55 55 55 Zone 6 45 45 45 45 45 Zone 5 45 45 45 4545 Zone 4 46 55 46 46 46 Zone 3 16 0 16 16 16 Zone 2 0 0 0 0 0 Zone 1100 70 100 100 100 Low Blow Position (mm) 170 245 170 170 170 LowPressure (bar) 10 6.5 10 10 10 High Blow Position 285 285 285 285 285(mm) High Blow Pressure (bar) 40 30 40 40 40 Preblow Flow (bar) 1 1 1 11 Body Mold Temp (° F.) 45 110 160 165 170 Base Mold Temp. (° F.) 45 9065 65 65 Preform Temp. (° C.) 78 82 76 76 75 Top Weight(g) 7.7 0 0 0 0Panel Weight(g) 23.3 0 0 0 0 Base Weight(g) 9.2 0 0 0 0 Weight(g) 0 0 00 0 7032D + 7032D + 7032D + 7032D + 7032D + 7032D + CM CM 80- CM 80- CM80- CM 80- CM 80- Resin 80-740-2 740-2 740-2 740-2 740-2 740-2 Speed(bph) 500 500 500 500 500 500 Overall 37 37 37 37 37 37 Oven LampSettings Zone 8 55 55 55 55 55 55 Zone 7 55 55 55 55 55 55 Zone 6 45 4545 45 45 45 Zone 5 45 45 45 45 45 45 Zone 4 46 46 46 46 46 46 Zone 3 1616 16 16 16 16 Zone 2 0 0 0 0 0 0 Zone 1 100 100 100 100 100 100 LowBlow Position 170 170 170 170 170 170 (mm) Low Pressure (bar) 10 10 1010 10 10 High Blow Position 285 285 285 285 285 285 (mm) High BlowPressure 40 40 40 40 40 40 (bar) Preblow Flow (bar) 1 1 1 1 1 1 BodyMold Temp 175 180 190 200 220 200 (° F.) Base Mold Temp. (° F.) 65 65 6565 65 110 Preform Temp. (° C.) 75 75 75 75 75 75

Thermal Stability—Bottles from condition Nos. 1-10 were placed in a 150°F. oven for 24 hours and then measured for dimensional changes. Notethat in these results, negative results represent shrinkage and positiveresults represent growth due to deformation.

Thermal Stability Results (Sets A1-A5) Variable Name Set A1 Set A2 SetA3 Set A4 Set A5 Mold Temperature (° F.) 200 45 Double 160 165 170 %Average −9.41% −8.48% −10.63% −10.43% −10.49% Height Change St Dev 0.97%0.80% 0.54% 1.54% 0.93% % Neck Average 0.17% −0.62% −1.94% −1.89% −2.54%Change St Dev 0.77% 0.45% 0.55% 0.68% 0.48% % Average n/a 8.36% 7.36%5.48% 6.16% Upper Label St Dev n/a 1.84% 2.49% 1.35% 2.14% Change %Average n/a −0.51% −1.28% −0.26% 1.11% Middle Label St Dev n/a 1.69%3.58% 4.56% 1.78% Change % Average n/a 5.79% 4.75% 4.50% 7.14% LowerLabel St Dev n/a 1.33% 1.32% 2.35% 1.21% Change

Thermal Stability Results (Sets A6-A10) Variable Name Set A6 Set A7 SetA8 Set A9 Set A10 Mold Temperature (° F.) 175 180 190 200 220 % HeightAverage −10.94% −8.86% −9.43% −8.45% −7.28% Change St Dev 1.20% 0.56%1.14% 0.77% 0.38% % Neck Average −3.59% −1.97% −3.27% −2.54% −2.48%Change St Dev 0.29% 1.33% 0.43% 0.54% 0.26% % Upper Average 7.08% 4.87%7.00% 7.28% 9.44% Label St Dev 1.14% 2.22% 1.42% 1.56% 1.30% Change %Middle Average −0.67% 0.93% 3.34% 3.87% 4.16% Label St Dev 3.34% 1.32%0.84% 0.67% 0.62% Change % Lower Average 6.01% 3.24% 6.30% 6.34% 7.25%Label St Dev 2.41% 1.34% 0.85% 0.81% 1.38% Change

While all of the bottles were distorted after storage in the oven, asthe mold temperature increased, there was a general trend of improvementin thermal stability. The double-blow process itself also helped withthe thermal stability.

Color/Haze Results—The sidewall of 1 bottle from each of the blowmolding conditions was measured for color and haze. Measurements weremade in two locations of the panel, the upper and lower panel. Ingeneral, the amount of haze in the upper panel was greater than in thelower panel of the same condition, and as the mold set point temperaturewas increased the amount of haze increased.

DSC Results—Differential scanning calorimetry was performed on thesebottles at a few different locations on the bottle to understand theeffect that mold temperature has on the crystallinity of the bottles. Asthe mold set point temperature increases the ΔH_(c) decreases, theΔH_(c) at 220° F. mold temperature and after double blowing. Tounderstand the effect of base temperature on the base crystallinity aDSC was also run on the double blown bottles, bottles molded at 220° F.(65° F. base, used as reference), and bottles blown using a 110° F. basetemperature were run. The ΔH_(c) of the 110° F. was slightly lower thanthe 65° F. The ΔH_(f) was similar for these two measurements. There wasnot a crystallization peak to measure for the double blown sample. Toverify that the double blow process was not changing the thermalcharacteristics of the finish, DSCs were performed on the finish from adouble blown bottle and the finish from a first pass bottle.

DSC Results Condition Location Tg ΔHc Tf ΔHf A1 - 45° F. Panel 63.25.336 165.6 23.1 A2 - 200° F. (Double) N/A N/A 164.6 22.7 A3 - 160° F.60.6 5.847 164.1 22.56 A4 - 165° F. 59.65 4.232 164.9 23.4 A5 - 170° F.61.75 4.434 165.4 24.18 A6 - 175° F. 60.07 2.632 165.01 23.14 A7 - 180°F. 62.89 3.095 165.07 24.56 A8 - 190° F. 60.02 1.699 164.6 24.25 A9 -200° F. 60.65 0.907 165.01 23.8 A10 - 220° F. 60.61 N/A 164.81 24.79A2 - 200° F. (Double) Base N/A N/A 165.57 22.41 A10 - 220° F. 60 16.2167.51 20.46 A11 - 200° F. (110° F. 57.8 14.61 167.04 20.01 Base) A2 -200° F. (Double) Finish 58.62 11.52 166.6 20.51 A10 - 220° F. 59.6512.51 166.74 19.26

The thermal stability of the containers improves as the blow moldtemperature increases and if the bottles are double blown. The mainshrinkage is in the base of the bottles and the thinner portions of thesidewall, however there are small amounts of deformation in the thickerportions of the sidewall. The haze and DSC results are consistent withincreasing crystallinity with increasing blow mold temperature.

Example 3

Overview—The focus of this bottle prototyping trial was to determinewhether the heat resistance of oriented, thick-walled PLA containers canbe improved through the heat setting process. A Boston round containermold with heat setting capability was used to produce bottles. The blowmold cavity for the Boston round container will be heated to allow thePLA to anneal during the blow molding step, however, the finish and baseareas remain amorphous due to the design of the blow molding and theneed to maintain a cold finish area to prevent deformation. The bottleswere evaluated for thermal stability, sidewall rigidity, haze and topload strength.

The feasibility of crystallizing the amorphous finish was also evaluatedby placing the finish into a hot oven to crystallize that region. Thesepreforms will then be blow molded under the optimized conditionsdetermined with untreated preforms. Alternatives to this process is toinclude a bottle design that has a blow and trim feature allowing thefinish area to be blown into the sidewall of the container.

Preform Design—A preform and tooling based on the target stretch ratiosof 3-4 hoop stretch and >2 axial stretch ratio to produce a containerthickness of 0.030″ was designed. This preform design allows for moreorientation in the base area, which leads to improved drop impactperformance.

Sampling—Preform samples were produced with two PLA resins, 7000D and7032D, along with a reheat additive and possible pigment. A reheatadditive was incorporated into all of the molded preforms to ensure thatthe reheat upon blow molding does not limit the process window. Once thepreforms were molded, twenty-five preforms were treated to crystallizethe threaded finish area while keeping the preform body cool to maintainits amorphous nature. These preforms were then held on spindles to avoidchanging the internal dimensions of the preform so that they can bereheated in the blow molding process. Once successfully crystallized inthe neck area, these preforms were blow molded under the optimizedconditions. A 16 oz. Boston round style container with a 33 mm finishwill be used in this blow molding trial. A champagne style base wasdesigned and utilized with this mold in an attempt to orient the PLAmaterial on the standing ring area where it will make contact duringdrop impact testing. This base push-up would also allow the material tobe more fully distributed throughout the center of the base area aswell. The bottle mold is heated through hot oil channels to heat set thePLA during the blow molding process. However, the finish and base areasare not heated during the blowing process and remain amorphous.

Forty preforms were available from the above procedure to setup and blowmold containers with a cold mold for thermal stability testing. Bottleswere blown at 2 blow molding conditions for testing.

Blow Molding—NatureWorks 7032 preforms (See example 2 above) were blowmolded using a Sidel SBO1/2 blow molding machine with mold temperaturesset at 45° F. Initially the optimized blow molding conditions from theprevious trial were attempted. At these conditions, the bottles werehazier in the neck area than they were in the previous trial and thematerial distribution was slightly different. The blow molding ovenheating profile was then adjusted in an attempt to produce bottles withthe same appearance and material distribution. During processing thesidewall thickness of several bottles were measured using a Magna-mikeand it was determined that the sidewall thickness difference betweenthese bottles and bottles made previously was 0.001″ or less. Bottleswere produced for testing at two conditions; the table below summarizesthe conditions used.

Resin 7032D + Toner 7032D + Toner Blow Molding Conditions Speed (bph)500 500 Overall 37 37 Oven Lamp Settings Zone 8 50 50 Zone 7 50 50 Zone6 40 45 Zone 5 60 45 Zone 4 55 40 Zone 3 20 25 Zone 2 20 20 Zone 1 97100 Low Blow Position 200 200 (mm) Low Pressure (bar) 14 14 High BlowPosition 270 270 (mm) High Blow Pressure 40 40 (bar) Preblow Flow (bar)2 2 Body Mold Temp (° F.) 45 45 Base Mold Temp. (° F.) 45 45 PreformTemp. (° C.) 79 77 Top Weight (g) 8.1 8.1 Panel Weight (g) 22 21.8 BaseWeight (g) 10.1 10.4

Twelve bottles were produced at these conditions. The second set ofconditions used were the best conditions found that produced bottleswith the closest sidewall thicknesses and haze appearance. Six bottleswere produced at these conditions.

Analytical Testing—Bottles were placed into an oven set to 125° C. for24 hours and their dimensional changes were determined. The results fromboth studies are contained in the following tables.

Thermal Stability Results (non-Heatset Bottles) Storage Diameter HeightVolume Temperature Change Change Change Sample Description (° C.) (%)(%) (%) 25106A1 7032D + Toner 125° C. 0.4 0.5 2.0 25106A2 7032D + toner125° C. 1.0 1.1 3.8

Thermal Stability Results (Heatset Bottles) Storage Diameter HeightVolume Temperature Change Change Change Sample Description (° C.) (%)(%) (%) 24748A 7000D 150° C. * * * 125° C. * * * 24748B 7032D + 150°C. * * * toner 125° C. 1.0 5.0 4.2

The bases of four of the twelve A1 bottles rolled out during testingcausing the bottles to not sit properly on a flat surface. Three of thesix A2 bottles tested also rolled out. The amount of shrink was less forthese bottles than the bottles that were blown using a heat set process.However, there were no rollout failures in the heatset bottles comparedto the 33-50% failure observed in the non-heatset bottles.

Example 4

Overview—Bottles were made for two PLA materials, 7000D and 7032D PLAsupplied by Natureworks, along with a toner/reheat colorant package.Although the 7032D bottles performed better, the thermal stabilitytesting did show a 4.2% shrinkage when those bottles were stored at 125°F.

Injection Molding—Following is a table identifying the variablesinjection molded during this trial.:

Material Variables Sample Description 24748A 7000D + toner 24748B7032D + toner

The PLA resin was dried at 176° F. for 4 hours to remove moisture priorto injection molding. The resin samples were injection molded on anArburg 420M reciprocating screw injection molding machine using a40.2±0.5 g preform tooling. An injection molding process was optimizedto achieve a clear part at the lowest possible injection moldingtemperatures and mildest conditions. Following are the preform moldingconditions.

24748 A Natureworks 7000D + 24748 B Colormatrix Natureworks 7032D +Variable Description 80-740-2 Colormatrix 80-740-2 Injection MoldingConditions Injection Date Nov. 26, 2007 Nov. 26, 2007 Machine #6 Arburg420 M #6 Arburg 420 M Preform # PRE-5568 1 PRE-5568 1 Preform Weight (g)40.2 40.3 Relative Humidity (% RH) 0% 41% Dew Point (° F.) 0 44 MoldTemp (° F.) 60 60 Ambient Temp (° F.) 0 68.5 Dryer Temp (° F.) 170 170Barrel Set-point Temperatures Feed (° C.) 211 211 Zone 2 (° C.) 209 210Zone 3 (° C.) 209 210 Zone 4 (° C.) 211 210 Nozzle (° C.) 206 205Injection 1st Injection Pressure (bar) 800 800 2nd Injection Pressure(bar) N/A N/A Injection Time (sec) 3.7 3.7 1st Injection Speed (ccm/sec)12.0 12.0 2nd Injection Speed (ccm/sec) 10.0 10.0 Holding PressureSwitch-Over Point (ccm) 8.0 8.0 1st Hold Pressure (bar) 250.0 250.0 2ndHold Pressure (bar) 200.0 200.0 3rd Hold Pressure (bar) 100.0 100.0 4thHold Pressure (bar) N/A N/A 1st Hold Pr. Time (sec) 2.0 2.0 2nd Hold Pr.Time (sec) 3.0 3.0 3rd Hold Pr. Time (sec) 2.0 2.0 4th Hold Pr. Time(sec) 0.0 0.0 Remain Cool Time (sec) 16.0 16.0 Dosage Circumf. Speed(m/min) 10.0 10.0 Back Pressure (bar) 25.0 25.0 Dosage Volume (ccm) 45.045.0 Meas. Dosage Time (sec) 6.8 6.1 Cushion (ccm) 7.4 7.6 AdjustmentData Cycle Time (sec) 32.7 32.8

Blow Molding—The PLA preforms were blow molded using a Sidel SBO1 blowmolding machine. Initially preforms were blown into a 16 oz Boston roundblow mold, CT-5568-1. The initial mold temperature setpoint was 270° F.The mold body temperature was reduced incrementally to 160° F. and themold base temperature was reduced to 47° F. At these temperatures, thebottles retained their shape after exiting the blow molding machine. Thematerial distribution was difficult to control for the 16 oz containerand an excess amount of the material in the neck area of the bottlecaused the bottle to not blow fully into the mold. This excess materialalso did not cool quickly enough in the mold and, therefore, deformedduring cooling outside of the mold. The machine speed, oven heatingprofile and mold temperature were adjusted in an attempt to distributethis material into the rest of the container, but none of the processingchanges were successful. As a result, an insert was added to the blowmold to make the bottle longer and provide more area for the material todistribute. Immediately after this insert was added, the excess ofmaterial in the neck area was removed and the shoulder was fully blown.Once the 18 oz, CT-5660-0, mold was installed, the processing conditionswere optimized to produce bottles with acceptable material distribution.Bottle section weights and sidewall thicknesses were used to determinematerial distribution. The NatureWorks 7000D bottles were produced usinga machine rate of 900 bottles per hour. For the 7032D bottles, twobottles were produced at machine speeds of 900, 700 and 500 bottles perhour. These bottles were filled with hot water at 150° F. and 160° F.The appearance of the bottles produced at 500 bph was better than thetwo higher machine speeds. This was a result of the slower machine speedand, therefore, more in-mold time allowing stresses to relax. Thefollowing table is a summary of blow molding conditions used to producebottles for testing.

Blow Molding Conditions Resin Natureworks 7000D + Natureworks 7032D +Colormatrix 80- Colormatrix 80- 740-2 740-2 Speed (bph) 900 500 Overall45 37 Oven Lamp Settings Zone 8 50 50 Zone 7 45 50 Zone 6 55 45 Zone 550 45 Zone 4 40 40 Zone 3 25 25 Zone 2 15 20 Zone 1 100 100 Low BlowPosition 270 200 (mm) Low Pressure (bar) 14 14 High Blow Position 255270 (mm) High Blow Pressure 40 40 (bar) Preblow Flow (bar) 2 2 Body MoldTemp (° F.) 160 160 Base Mold Temp. (° F.) 47 47 Preform Temp. (° C.) 8177 Top Weight (g) 8 8.2 Panel Weight (g) 21.9 21 Base Weight (g) 10.310.7

Drop Impact Testing—To determine the drop impact strength of thecontainers, bottles were filled with 18 oz. of water, refrigerated for24 hrs to 40° F. and dropped vertically onto a flat marble platform. ABruceton staircase method was used to determine the average failureheight starting from an initial height of 60 inches using increments of6 inches. For this method, 21 bottles were dropped. Failure is definedas any leakage of contents not resulting from closure failure. For the7032 bottles, no failures were observed during the testing. The resultsare contained in the following table, including those from the previousdrop impact testing with the Nalgene® bottles.

Drop Impact Result Failure Height Work Request Description (in) 23663A16 oz Nalgene ® 101.0 ± 12.2  24748A 7000D + toner 96.0 ± 10.2 24748B7032D + toner 114 ± 0 

Thermal Stability Testing—Six filled bottles were placed into an oven at150 or 125° C. for 24 hours and their dimensional changes weredetermined. At the 150° C. temperature setting, all bottles weredistorted and meaningful measurements could not be taken, thus thethermal stability study was repeated at the lower 125° C. temperature todetermine the stability there. Bottle diameters and volumes wereevaluated both before and after subjecting the bottles to the elevatedtemperatures. The results are contained in the following table.

Thermal Stability Results Volume Storage Temperature (° C.) HeightChange Description Diameter Change (%) Change (%) (%) 7000D + toner 150°C. * * * 125° C. * * * 7032D + toner 150° C. * * * 125° C. 1.0% 5.0% 4.2

Container Color Testing—Six bottles from the optimized conditions foreach material were evaluated for preform color in L*a*b* (CIELAB) colorspace according to ASTM D1003-61 using a Minolta Color meter. Preformswere cut in half and then placed onto a fixture to allow the sidewall tobe flush against the light source. In interpreting this informationshown below, the following general guidelines are available:

L: 100=white; 0=blacka*: positive=red; negative=green; 0=grayb*: positive=yellow; negative=blue; 0=gray

ΔE=L _(i)−((L _(std))₂+(a _(i) −a _(std))₂+(b _(i) −b _(std))₂)

Haze—measure of light scattering through the sample; a higher numberimplies less light going through the sample. The results are containedin the following table.

Container Color Results Description L* a* b* Haze 7000D + toner 94.970.06 1.45 3.67 7032D + toner 95.04 0.08 1.37 3.75

Sidewall Rigidity—Bottles were tested to determine the amount of forcerequired to deflect the sidewall label panel ½ inch with a 5/16 inchprobe at a crosshead speed of 20 in/min. Test bottles were marked atfour locations around the bottle, 90 degrees apart, and the sidewallrigidity was determined at each point. The 0 degree mark is on a partingline. The sidewall rigidity testing has no established specifications.

Sidewall Rigidity Results 0° 90° 180° 270° Resin Average Average AverageAverage Description Force (lbf) Force (lbf) Force (lbf) Force (lbf)7000D + toner 18.4 18.4 18.4 18.0 7032D + toner 19.2 20.2 20.1 18.9

FIGS. 3A-3C show an exemplary embodiment of a PLA bottle 300 producedaccording to one or more of the manufacturing methods described above.It should be understood that the example of FIG. 3 is just that, anexample, an many variations to the size, dimensions, appearance, andlook of the example in FIG. 3 are contemplated by the scope of thepresent disclosure and invention.

While aspects of the present invention have been described withreference to the specific embodiments thereof, it should be understoodby those skilled in the art that various changes may be made andequivalents may be substituted without departing from the true spiritand scope of the invention as defined by the appended claims. Inaddition, many modifications may be made to adapt a particularsituation, material, composition of matter, method, process step orsteps, to the objective, spirit and scope of the present invention. Allsuch modifications are intended to be within the scope of the claimsappended hereto. In particular, while the methods disclosed herein havebeen described with reference to particular steps performed in aparticular order, it will be understood that these steps may becombined, sub-divided, or re-ordered to form an equivalent methodwithout departing from the teachings of the present invention.Accordingly, unless specifically indicated herein, the order andgrouping of the steps is not a limitation of the present invention.Specifically, the following options, additional embodiment, andalternatives are contemplated.

The PLA resin may be selected from the class of polyhydroxy alkanoates.

The polylactic acid polymer may be (a) a copolymer having repeating Land D lactic acid units in which either the L or D lactic acid units arethe predominant units or (b) a blend of such copolymers wherein thepredominant repeating units in the copolymer or blend constitute90-99.5% of the lactic acid enantiomer repeating units in the PLA resinor blend.

The containers are clear containers capable of passing the industrystandards for durable containers.

The containers do not have extractable levels that are suspected orknown to have any affect on human health.

The renewable resource based thermoplastic resin has sufficientmolecular wt. melt strength and viscosity to successfully produce adurable thick walled container.

The container has sufficient stress induced and quiescent crystallinityto produce a heat stable and impact resistant container capable ofmeeting the industry performance standards for Polycarbonate bottles.

The PLA resin has a number average molecular wt of 80000-150000 asmeasured by gel permeation chromatography using a polystyrene standard.

92-99% of the lactic acid enantiomer repeating units in the PLA are ofthe predominant lactic acid enantiomer.

The formed container has sufficient stress induced and quiescentcrystallinity to produce a heat stable and impact resistant containercapable of meeting the industry performance standards for Polycarbonatebottles

1. An injection stretch blow molding process for making containers froma polylactic acid resin, comprising: molding the polylactic acid resininto a preform; applying heat to the preform; stretching and blowing theperform in axial and radial dimensions in order to form a preliminarymolded container; conditioning the molded container pursuant to a firstconditioning method; conditioning the molded container pursuant to asecond conditioning method; and stretching and blowing the moldedcontainer in order to form a final molded container.
 2. The injectionstretch blow molding process of claim 1, wherein applying heat to thepreform is performed substantially contemporaneously with molding thepolylactic resin into a preform.
 3. The injection stretch blow moldingprocess of claim 1, wherein applying heat to the preform is performedsubsequent to the molding of the preform.
 4. The injection stretch blowmolding process of claim 3, wherein applying heat to the preform isperformed after the molded preform has cooled.
 5. The injection stretchblow molding process of claim 1, wherein conditioning the moldedcontainer pursuant to a first conditioning method comprises raising thetemperature and pressure of the molded container for a fixed period oftime.
 6. The injection stretch blow molding process of claim 1, whereinconditioning the molded container pursuant to a first conditioningmethod comprises direct contact heat setting.
 7. The injection stretchblow molding process of claim 1, wherein conditioning the moldedcontainer pursuant to a first conditioning method comprises heat settingin an oven.
 8. The injection stretch blow molding process of claim 1,wherein conditioning the molded container pursuant to a firstconditioning method comprises raising the temperature of the moldedcontainer to a temperature above the glass transition temperature of thepolylactic resin.
 9. The injection stretch blow molding process of claim1, wherein the first conditioning method and the second conditioningmethod are the same.
 10. The injection stretch blow molding process ofclaim 1, wherein conditioning the molded container pursuant to a firstconditioning method comprises raising the pressure of the moldedcontainer to a predefined pressure.
 11. The injection stretch blowmolding process of claim 1, wherein conditioning the molded containerpursuant to a second conditioning method comprises raising the pressureof the molded container to a predefined pressure.
 12. The injectionstretch blow molding process of claim 1, wherein the polylactic resin isa copolymer having repeating L and D lactic acid units in which eitherthe L or D units are the predominant repeating units and the predominantrepeating units constitute 90 to 99.5% of the lactic acid repeatingunits.
 13. The injection stretch blow molding process of claim 1,wherein the polylactic resin is a blend of copolymers wherein thepredominant repeating units in the blend of copolymers constitute 90 to99.5% of the lactic acid enantiomer repeating units.
 14. The injectionstretch blow molding process of claim 1, wherein 92 to 99% of the lacticacid enantiomer repeating units in the polylactic resin are of thepredominant lactic acid enantiomer.
 15. The injection stretch blowmolding process of claim 1, wherein the polylactic resin includes atleast one additive.
 16. The injection stretch blow molding process ofclaim 15, wherein the additive is selected from the group consisting ofa colorant and a thermal stabilizer.
 17. A container formed from apolylactic acid-based resin through an injection stretch blow moldingmanufacturing process, the manufacturing process comprising: molding thepolylactic acid resin into a preform; applying heat to the preform;stretching and blowing the perform in axial and radial dimensions inorder to form a preliminary molded container; conditioning the moldedcontainer pursuant to a first conditioning method; conditioning themolded container pursuant to a second conditioning method; andstretching and blowing the molded container in order to form a finalmolded container.
 18. The container of claim 17, wherein the averagesidewall thickness of the container is greater than 40 mils.
 19. Thecontainer of claim 17, wherein the average sidewall thickness of thecontainer is greater than 60 mils.
 20. An injection stretch blow moldingprocess for making containers from a polylactic acid resin, comprising:molding the polylactic acid resin into a preform; raising thetemperature of the preform to between 60° C. and 80° C.; stretching andblowing the perform in axial and radial dimensions in order to form apreliminary molded container; raising the temperature of the moldedcontainer to between 60° C. and 100° C.; and stretching and blowing themolded container in order to form a final molded container.